Advanced technologies (e.g., virtual and augmented reality) may provide new possibilities to facilitate control room (CR) design and evaluation activities. We studied how immersive three-dimensional (3-D) virtual reality environments may augment and advance the evaluation of safety-critical nuclear power plant CR systems. A multiuser functionality enables several operators to be located and to collaborate in the same virtual CR environment at the same time. There is also a realistic representation of emergency operating procedures in the virtual CR. Spatial audio communication through headsets makes the experience even more realistic. The paper addresses both technical and human factors issues associated with the use of immersive 3-D virtual reality environments in CR validation tests, for example, the amount of technical resources required as compared to normal validation in a real-life physical simulator environment, creation of methodologically new testing opportunities, and new opportunities for data registration and analysis. A new framework has been established for estimating the needed fidelity level of the virtual CR for the type of system evaluation at hand.